1. Field of the Invention
This invention relates to a steering system for a watercraft vehicle powered by a jet propulsion unit. More particularly, this invention relates to a novel apparatus for controlling steering and movement of a watercraft vehicle when the engine is operating at a reduced speed and a means for controlling the thrust of the water exiting the jet propulsion unit at corresponding low engine speeds.
2. Discussion of Related Art
Directional control of watercraft vehicles depend upon the thrust of the water exiting a jet propulsion unit. As the thrust of the water exiting the venturi and the exit nozzle of the jet propulsion unit decreases so does the engine speed of the watercraft vehicle. A conventional jet propulsion unit 210 for a watercraft is shown in FIG. 7 and is comprised of an inner housing and an outer housing. The outer housing comprises a water inlet portion 215 for allowing water into the propulsion unit. At low speed, the jet propulsion unit 210 creates a vacuum force at the intake through which the water travels. In a preferred embodiment, the water inlet portion is comprised of an intake grate like member, as shown at 215. The intake grate is attached to the outer housing by means of screws at a distal end of the outer housing, and it allows for the free flow of water while protecting the jet propulsion unit 210 and its parts, such as an impeller 242, from pulling any harmful debris into the jet propulsion unit 210.
The outer housing further comprises a support 218 at a proximal end for receiving the impeller 242, an impeller housing assembly 240, and a venturi 230. The support 218 comprises a circularly shaped aperture extending through the center of the support 218, and is adapted for receiving the impeller 242. In addition, the support 218 comprises a means for receiving the impeller housing assembly 240 and is secured thereto by means of fasteners and o-rings. The support 218 and the impeller housing assembly 240 are both adapted for receiving the impeller 242 and its associated wear-ring 246. The impeller 242 comprises a plurality of blades 248 and a wear-ring 246 which surrounds the impeller 242 as it spins. The impeller 242 spins inside very tight tolerances within the propulsion unit 210. The wear-ring 246 surrounds the impeller 242 such that if there is a problem the impeller 242 will damage an easy to replace item instead of the entire jet propulsion unit 210. The impeller 242 further comprises an impeller shaft 244 which is connected to the drive shaft of the engine through the impeller 242 The drive shaft of the engine causes the impeller 242 to rotate during use of the watercraft vehicle. At low speed, it is the rotation of the impeller 242 which creates a vacuum that pulls water into the inlet 215 of the jet propulsion unit 210. As the water approaches the rotating impeller 242, the blades 248 of the impeller 242 force the water toward a venturi 230 and a steering nozzle 228 at a stem end of the vehicle. It is the thrust created by the water mass accelerating in the venturi 230 which forces water through the jet propulsion unit 210 and moves the vehicle. The configuration of the jet propulsion unit 210 together with the impeller 242 allows the spinning impeller 242 to thrust water through the venturi 230.
The impeller 242 which is surrounded by a wear-ring 246 is further enclosed within an impeller housing 240 comprising a distal end 241 and a proximal end 249. The distal end 241 of the impeller housing 240 comprises a plurality of apertures for receiving attaching means and securing the impeller housing 240 to the support 218. The proximal end 249 of the impeller housing 240 has a plurality of apertures for securing the impeller housing 240 to a nozzle assembly 250. The impeller housing 240 further comprises stator vanes 224 formed integrally within the impeller housing 240. The spinning action of the impeller 242 causes the water to leave the impeller housing 240 in a swirling torrent of inefficient force. The stator vanes 224 located aft of the impeller 242 function to align the water as it moves away from the impeller housing 240. Attached to a proximal end of the impeller housing 249 is a thrust cone 226 for directing the water to the nozzle assembly 250. The thrust cone 226 controls the acceleration of the water as it exits the stator vanes 224 during its acceleration through the nozzle assembly 250.
The nozzle assembly 250 is attached to the secondary housing by means of screws. The steering nozzle 228 works to push the exiting water rearward in a controlled stream of propulsion. As shown in FIG. 1, the venturi 230 is distal of the steering nozzle 228 and functions to control the thrust and velocity of the water flow exiting the impeller housing 240. Accordingly, the water exiting the venturi 230 enters the steering nozzle 228 which redirects the water exiting the jet propulsion unit 210, allowing for controlled maneuvering of the watercraft vehicle.
Typically, the directional control and movement of the watercraft vehicle at low speeds has been through activating the engine throttle to increase engine speed and create an increased thrust from the water exiting the jet propulsion unit. In general, the throttle controls the thrust of the water passing through and exiting the jet propulsion unit by regulating engine speed, thereby controlling the speed of the vehicle and allowing the operator to move a steering helm wheel, or a similar means, to control the directional movement of the vehicle. Accordingly, it has become common practice in the art for an operator to manually utilize the throttle together with the steering helm wheel in order to regulate the direction and velocity of water exiting the jet propulsion unit, thereby controlling the watercraft vehicle""s direction for travel.
Several steering control apparatus for watercraft vehicles have been patented. The steering control apparatus disclosed in the Prior Art comprise means for controlling the direction of the fluids exiting the nozzles, thereby controlling the direction of travel of the vehicle. However, none of the patents disclose a means for controlling movement of the watercraft vehicle at low speeds by means of activating and controlling the carburetor and the air-fuel mixture being supplied to the carburetor. Furthermore, the Prior Art fails to disclose means for controlling the thrust and directional control of the vehicle at low speeds through the exclusive use of the steering helm assembly.
Therefore, what is desirable is a novel steering apparatus for a jet propulsion unit for a watercraft vehicle having a means for controlling the air-fuel mixture of the carburetor and corresponding internal combustion engine, wherein the thrust of the water exiting the venturi and corresponding exit nozzle may be alternatively controlled by the steering helm assembly or a series of electronic sensors and switches. The apparatus is variable among several different positions so that the steering helm assembly or an electronic control means may each be alternatively activated to control the thrust as well as directional movement of the vehicle during alternative riding conditions when the engine speed is low or reduced.
It is therefore the general object of the present invention to provide a low speed steering system for a watercraft vehicle for controlling and enhancing the directional movement of a watercraft vehicle at such speeds.
It is a further object of the invention to provide a plurality of cables within the low speed steering system for controlling the thrust of the jet propulsion unit by means of the steering helm assembly. By placing the throttle control in an off position, the operator may control the thrust of the water exiting the jet propulsion unit exclusively by means of the steering helm.
It is an even further object of the invention to provide an electronic control means within the steering system for applying a minimal thrust to the jet propulsion unit. At such time as the throttle is set to an off position, the electronic control means may provide a minimal thrust to the jet propulsion unit for enhancing docking and other directional movements of the watercraft vehicle.
Furthermore, it is a further object of the invention to provide a biasing means for controlling the air-fuel mixture flowing into the carburetor of the watercraft vehicle. A plurality of cables or electronic sensors and switches are connected to a carburetor biasing means for alternatively controlling the air-fuel mixture flow into the carburetor.
Another object of the invention is to control the thrust of the engine and the directional control of the vehicle by means of rotating the steering helm assembly in a given clockwise or counter-clockwise direction. By setting the throttle to an off position, the directional control of the vehicle together with the thrust of the water exiting the jet propulsion unit may be controlled by means of the steering helm assembly.
It is an even further object of the invention, to provide a plurality of cables, a cable support and a slide coupler means connecting the throttle and the steering helm assembly to a biasing means for the carburetor. The slider coupler means, together with the cable support, function to control the carburetor actuator means and to allow either the throttle or the steering helm assembly to control the thrust of the water exiting the jet propulsion unit.
In accordance with the invention, these and other objectives are achieved by providing a low speed steering system comprising a novel means for controlling the thrust of the water exiting the jet propulsion unit for enhancing docking and other directional control movements of a watercraft vehicle. Accordingly, the novel low speed steering system configuration enables an operator of the vehicle to directionally control steering of the watercraft vehicle by means of the steering helm assembly when the throttle is set in an off position.